Sunless tanning agents are formulated into two types of cosmetic products. Of these, the most traditional is the self-tanning lotion. The imparted benefit is to achieve a skin coloration equivalent to that from basking in the sun. More recently, a second product category has arrived. Therein a sunless tanning agent in small amounts is added to a typical moisturizing lotion. A “glow or shine” is thereby imparted. Glow or shine is a major factor in the appearance of healthy looking skin.
Most prominent among the sunless tanning agents is dihydroxyacetone (“DHA” which is also chemically known as 1,3-dihydroxy-2-propanone). DHA, after application, is believed to exert its effect through interactions between its hydroxyl groups and the amino groups of amino acids and peptides naturally occurring in the hydrolipid pellicle and first layers of the stratum corneum of the skin. These so-called Maillard reactions are believed (see, e.g., Bobin et al., J. Soc. Cosmet. Chem. 35: 255 (1984)) to lead to formation of brown pigments in the skin, thereby giving it an appearance similar to that of a naturally obtained tan.
Unfortunately, many sunless tanning products available on the market are not stable in that they turn a yellow and/or orange color after application, especially when exposed to UV light. Other sunless tanning products perform poorly and do not quickly impart a noticeable brown color after application. Such poorly performing products do not prevent “tan-happy” consumers from basking in the sun. Products that underperform, therefore, do not protect consumers from the sun's ultraviolet rays.
There is increasing interest to develop compositions and methods for imparting a sunless tan, and especially, compositions that are storage stable. This invention, therefore, is directed to a composition and method that employ a sunless tanning agent as well as an adjuvant for the sunless tanning agent. The composition employs a pyranone, furanone and/or a derivative thereof as an adjuvant and, when applied, unexpectedly results in the consumer having skin with a brownish/tan coloration within a consumer acceptable time. Surprisingly, such a composition does not result in color body generation even when the sunless tanning agent and adjuvant are stored together in a monophase.
Additional Information
Efforts have been disclosed for making self-tanning cosmetic compositions. In U.S. Pat. Nos. 5,232,688 and 5,612,044, self-tanner compositions with DHA are described.
Other efforts have been disclosed for making self-tanning compositions. In U.S. Pat. No. 5,750,092, compositions with DHA and secondary amines are described.
Still other efforts have been disclosed for making self-tanning compositions. In U.S. Pat. No. 6,231,837, self tanning formulations comprising DHA, polyethoxyglycol and a polyol are described.
None of the additional information describes a method and/or composition that yield excellent sunless tanning results whereby the composition and method employ a sunless tanning agent and a pyranone, furanone, derivative thereof or mixture as an adjuvant.